/* -*- mode: C -*-  */
/* 
   IGraph R library.
   Copyright (C) 2011-2012  Gabor Csardi <csardi.gabor@gmail.com>
   334 Harvard street, Cambridge MA, 02139 USA
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
   02110-1301 USA

*/

#include <igraph.h>
#include <stdio.h>

#define N 1000

igraph_bool_t has_loops(const igraph_t *graph) {
  int i, n=igraph_ecount(graph);
  for (i=0; i<n; i++) {
    if (IGRAPH_FROM(graph, i) == IGRAPH_TO(graph, i)) { return 1; }
  }
  return 0;
}

igraph_bool_t has_multiple(const igraph_t *graph) {
  igraph_bool_t res;
  igraph_has_multiple(graph, &res);
  return res;
}

#define ERR() do {				\
  printf("Seed: %d\n", seed);			\
  igraph_write_graph_edgelist(&ws, stdout);	\
  } while (0)

#define SEED() do {							\
    seed=igraph_rng_get_integer(igraph_rng_default(), 1, 10000);		\
    igraph_rng_seed(igraph_rng_default(), seed);				\
  } while (0)

int main() {
  
  igraph_t ws;
  igraph_bool_t sim, seen_loops, seen_multiple;
  int i, seed=1305473657;

  igraph_rng_seed(igraph_rng_default(), seed);
  
  /* No loops, no multiple edges */
  for (i=0; i<N; i++) {
    SEED();
    igraph_watts_strogatz_game(&ws, /*dim=*/ 1, /*size=*/ 5, /*nei=*/ 1,
			       /*p=*/ 0.5, /*loops=*/ 0, /*multiple=*/ 0);
    igraph_is_simple(&ws, &sim); if (!sim) { ERR(); return 1; }
    if (has_loops(&ws)) { ERR(); return 1; }
    if (has_multiple(&ws)) { ERR(); return 2; }
    igraph_destroy(&ws);
  }

  /* No loops, multiple edges possible */
  seen_multiple=0;
  for (i=0; i<N; i++) {
    SEED();
    igraph_watts_strogatz_game(&ws, /*dim=*/ 1, /*size=*/ 5, /*nei=*/ 1,
			       /*p=*/ 0.5, /*loops=*/ 0, /*multiple=*/ 1);
    if (has_loops(&ws)) { ERR(); return 3; }
    seen_multiple = seen_multiple || has_multiple(&ws);
    igraph_destroy(&ws);
  }  
  /* This might actually happen */
  /* if (!seen_multiple) { return 4; } */

  /* Loops possible, no multiple edges */
  seen_loops=0;
  for (i=0; i<N; i++) {
    SEED();
    igraph_watts_strogatz_game(&ws, /*dim=*/ 1, /*size=*/ 5, /*nei=*/ 1,
			       /*p=*/ 0.5, /*loops=*/ 1, /*multiple=*/ 0);
    if (has_multiple(&ws)) { return 5; }
    seen_loops = seen_loops || has_loops(&ws);
    igraph_destroy(&ws);
  }
  /* This might actually happen */
  /* if (!seen_loops) { return 6; } */
  
  /* Both loops and multiple edges are possible */
  for (i=0; i<N; i++) {
    SEED();
    igraph_watts_strogatz_game(&ws, /*dim=*/ 1, /*size=*/ 5, /*nei=*/ 1,
			       /*p=*/ 0.5, /*loops=*/ 1, /*multiple=*/ 1);
    seen_loops = seen_loops || has_loops(&ws);
    seen_multiple = seen_multiple || has_multiple(&ws);
    igraph_destroy(&ws);
  }
  /* This might actually happen */
  /* if (!seen_loops) { return 7; } */
  /* if (!seen_multiple) { return 8; }   */

  return 0;
}
